Process of purifying waste mercerization-lyes.



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UNITED STATES PATENT OFFICE.-

OTTO VETITER, OF GHEMNITZ, GERMANY.

PROCESS .OF PURIFYING WASTE MERCERIZATION-LYES.

No Drawing.

To all whom it may concern;

Be it known that T, O'r'ro VENTER, a subject of the German Emperor, andresiding at Chemnitz, Germany, have invented a certain new and usefulImproved Process of Purifying Waste Mercerization-Lyes, of which thefollowing is a specification.

The subject matter of the present invention is an improved process forpurifying waste mercerization lyes.

After the soda-lye is removed from the piece of fabric impregnated withsoda-lye this waste lye contains soluble starch, dextrin and apercentage of sodiumcarbonate. Now the object of this invention is toremove these impurities. For this purpose the waste is to be treatedwith such a quantity of caustic lime that is considerably greater than.the quantity requisite for the caustification.

lt maybe mentioned by way of example that 209 liters of waste-lye arebrought. to boiling, after which 100 kilograms of caustic lime are addedand as well 30 kilograms soda, the whole being heated until thecaustification is completed. Thereby a precipitate is obtained, whichmust be removed. The percentage'of the impurities above mentioncd isthereby reduced from 2% to 0.2%. Of the 100 kilograms of lime only 10 to15 or less would be necessary for the caustification.

A modification of the process consists in substituting one portion ofthe lime by strontia or baryta. By adding strontia or barytaa slimypreclpitate is produced, which is completely carried down by theexisting precipitate of lime. The purifying takes place almostinstantaneously.

Example: To 1 cubic meter of the above mentioned waste-lye of 12 Baumare added 100 kilograms barium hydrate, 100 kilograms lime and 30kilograms calcined soda. The waste-lye jisfirst heated to boiling, the,barium hydrate, previosuly dis-' solved in hot water, is then addedthereto and after some time the lime is added and Specification ofLetters Patent. Patented Aug. 16, 1910. Applieationfiled March 2, 1908.Serial No. 418,900.

finally the carbonate of soda, after which the whole is heathdpreferably by a gentle simmer at about 100 C. until the caustificationis completed. It is then allowed to cool down to about to 80 C. andfiltered or separated by settling and decantation. The

precipitates obtained, which still contain a small quantity of lye arethen Washed with water, which water may be employed for the nextpurifying operations, for lnstance to dissolve the soda. Theprecipitates thus treated may be regenerated in some of the customaryways, for example, by mixing the same with coal-dust, pressing themixture into bricks and heating the latter red hot in a reverberatoryfurnace. An almost equally good result is obtained if, in working asabove 250 kilograms of lime are employed together with 10 kilogramsbarium hydrate.

ll claim I l. The process of purifying waste mercerizatio-n lyes,consisting in boiling the lye, then adding thereto a quantity of causticlime and a hydrate of another alkaline earth metal dissolved in hotwater, which quan v tity isconsiderably .in excess of the quantityrequisite for caustification, then adding soda thereto, heating thewhole until the caustification iscompleted', whereby a precipitate isobtained, and then removing the precipitate.

2. The rocess of purifying waste mercerization yes, consisting inboiling the lye, adding thereto barium hydrate dissolved in hot water,then adding a quantity of caustic lime, which is considerably in excessof the quantity of lime requisite for caustification, then adding sodathereto,;heating the whole until the caustification action is completed,whereby a precipitate is obtainedand then removing the precipitate.

In testimony whereof, I affix my signature in the presence of twowitnesses.

